I couldn't replicate it. Could you share a screenshot of your options on the quiz? Particularly answer type and text match may be helpful. It is interesting that the H2O shows up, but the answers that seem to be numbers didn't, so are the settings different between the two?
You should try zooming in or out in the browser (one set of shortcuts for that is control = and or control -, respectively). That might work automatically, or you might need to refresh the page.
If that doesn't work, as a temporary workaround for the already submitted quizzes, you might try double-clicking right next to the boxes, and then pressing control-C, that might copy the (invisible) text in the box, and then you can paste it (control-V) elsewhere.